The aims of this program project from the Southwest Pediatric Nephrology Study Group are: 1) to define the clinical course of a series of poorly understood renal disorders in children and to undertake prospective therapeutic trials in these disorders where appropriate; 2) to study the complications of chronic, progressive renal insufficiency in childhood; and 3) to evaluate methods of treatment for end-stage renal disease (ESRD) in childhood. These aims will be achieved by multicenter collaborative studies in the 10 centers listed in this proposal. The overall goal of our proposal will be to increase knowledge of different stages of renal disease; this will be achieved by the following specific studies: 1) Study of the clinical course and evaluation of clinco-pathologic correlations in a) idiopathic IgA nephropathy (Berger's Disease); b) nephrotic syndrome associated with diffuse mesangial hypercellularity; c) nephrotic syndrome associated with focal segmental glomerulosclerosis; d) membranous glomerulonephropathy; e) membrano-proliferative glomerulonephritis; f) mild or moderate vesico-ureteric reflux; and g) idiopathic hypercalciuria associated with hematuria. A prospective trial of intravenous high-dose methylprednisolone and oral prednisone in proliferative glomerulonephritis associated with systemic lupus erythematosus will also be undertaken. 2) The following inter-related complications of chronic progressive renal insufficiency will be studied: a) nutrition; b) renal osteodystrophy; c) anemia; and d) growth. 3) The main focus of our studies of childhood ESRD will be the evaluation of methods of prolonged dwell peritoneal dialysis (CAPD and CCPD). Technical aspects (e.g.: catheter problems, peritonitis) of these modalities will be assessed, and the effects of each treatment on nutrition, renal osteodystrophy, anemia and growth will be studied. The documented close cooperation of the centers listed in this proposal will enable the studies to be conducted in an efficient and scientifically accurate manner such that in the next five years we will obtain answers to many of the questions existing today in Pediatric Nephrology.